dabao1955 cd1df50a2a Complete the xvmp IR virtualizer end to end and measure the de-virtualization chain on a real fixture ...

The public xvmp tree ships a compiler half that was never compiled (no TU
includes the virtualizer headers; on dev trees they do not build), a weak
empty vm_exec stub, silent skips for unsupported IR, and a companion article
describing an earlier prototype that is not in the tree. This change completes
and measures the chain:

- Completed toolchain, merged into all four omp branches of that tree: gated
  new-PM pass wiring (-mllvm -irobf-irvm, section .irvm), FORMAT v3 bytecode
  (8-byte aligned slots, explicit load/store widths, stable CC_ cast kinds,
  per-index GEP byte scales, branch condition = operand 0), a strong-symbol
  vm_exec interpreter with a 23-check unit suite, and a VMP.h user header.
  Virtualized vs native output identical at -O0/-O1/-O2 on all four
  branches. One branch's ungated IRVM call in Obfuscation::runOnModule
  (rewrote .irvm functions in plain native builds) removed; IRVM is
  strictly flag-gated.

- Fixture measured end to end (fco+bcfobf+subobf+IRVM build): native-identical
  output; 17,961-step guest trace via VMP_TRACE; 24.6M-instruction host trace
  via a ptrace single-stepper; vm_handler_slice yields 95,184 segments / 18
  unique signatures; the fla outer state machine separates as a shuttle class,
  round-boundary segments split the trajectory, positional alignment names
  every handler segment (59/59 in a round; counts match the guest histograms
  exactly), zero unmapped with --opcode-map.

- Tooling hardening measured on the real fixture: opcode maps key by
  signature (first-block keys collide under a shared dispatch successor);
  apply_map keeps first-block keys as fallback, regression tests added.

- Environment boundary recorded: frida stalker does not work in these
  containers (measured past the syscall layer: primitives pass, agent loads,
  zero denied syscalls; the failure is inside the injected agent's hook
  machinery), an outer ptrace tracer conflicts with frida spawn, and the
  ptrace stepper is the working host capture path. Design lesson: a pure
  virtualized call can still be LICM-hoisted by the compiling optimizer.

Records: EXTENSION-sampling-crash.md SS5-SS6 (final-state rewrite),
known-limitations.md, ete-diff-tracing.md SS5, vm_handler_slice.py header,
capability matrix.

2026-10-16 14:45:03 +08:00

..

tool-verification

Complete the xvmp IR virtualizer end to end and measure the de-virtualization chain on a real fixture

2026-10-16 14:45:03 +08:00